I think it was my idea. One of the major motivations for using a text-based format (versus the unfortunate de facto standard, Microsoft Word) was integration with good developer tools and workflow.

Our manuscript and all our project code was in a Subversion repo, so each author always had the latest updates. HTML generated from the Markdown files was great for generating nice printed/printable output too.

We could have used any number of similar formats: Markdown, Textile, reStructuredText. If we did it again we'd probably use reST plus Sphinx. That would grant all the same advantages, plus give us a little more formatting flexibility and tool support.

This workflow enabled certain kinds of programmatic action on our text, notably two things: automated testing of the interactive examples within the text, and automated extraction of example snippets from source code files.

There's a little documentation in the docstrings of the scripts. Here's the summary:

To test code snippets in the manuscript file: test_snippets.py example/text.txt

To extract code from source files into the manuscript file: try_excerpt.py example/text.txt

Authors, make use of this if you can — or maybe even better, take inspiration from the idea and implement a system of your own.